Hoop and counter-hoop tuning device for a drum

ABSTRACT

A drum includes a drum shell, a drum head, a counter-hoop and a shell hoop. A drum skin extends over the open end of the drum shell and has a circumferential bead. The counter-hoop has a downwardly and outwardly extending flange which bears on the bead. The shell hoop has a rim which extends upwardly and outwardly. An adjustable clamp ring engages the flange of the counter-hoop and the rim of the shell hoop through correspondingly inclined portions. The clamp ring has a breach and a tightening mechanism so that when the clamp ring is tightened, the counter-hoop is forced downwards, thereby tightening the skin.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to drums, that is to say percussioninstruments, such as snare drums, tom-toms, bass drums, tympanis, andthe like. The invention is particularly concerned with the tuning ofdrum heads.

2. Description of Related Art

In conventional drums, the skin of the drum head is stretched over theopen end of a cylindrical drum shell and is held in position by means ofa counter-hoop which bears on the rim of the head. The skin is tensionedby means of tensioning bolts which act on the counter-hoop and engagetapped fittings fixed to the drum shell. When these bolts are tightened,the counter-hoop is urged against the rim, thus tensioning the skin.

In order to ensure that the skin is evenly tensioned and is therefore"tuned", it is necessary to adjust minutely each of the bolts, which areusually at least six or eight in number. This procedure is complicatedby the fact that when one bolt is adjusted it has differing effects onthe tension in the skin produced by the other bolts, making tuning avery time consuming and skilled operation.

Two related proposals which seek to address this disadvantage aredescribed in British Patent Nos. 1488167 and 1558045. In the first ofthese references, the counter-hoop has a series of circumferentiallylocated inclined slides which each engage a pair of rollers which arefixed to the shell. The rollers in each pair are offset to define anangle of inclination which corresponds to the inclination of the slides.Thus, as the counter-hoop is rotated in one sense, the slides androllers engage, drawing the counter hoop down against the head rim andso tensioning the head. Rotation in the other sense has the oppositeeffect. The counter-hoop is rotated by means of a rack which is fixed tothe counter-hoop, and a pinion fixed to the shell; as the pinion isrotated, the rack is driven circumferentially. The arrangement shown inthe second reference is very similar except that the rollers arereplaced by inclined nylon blocks.

A disadvantage of these arrangements is that even tensioning is stilldifficult to achieve in practice, partly due to unevenness andimperfections in the heads and partly due to the difficulties inattaching the rollers or blocks accurately to the shell.

This problem is addressed in the present Applicant's co-pendingapplication No. 9511862.6 which provides a drum comprising: a drumshell; a drum head having a skin extending over an open end of the shelland a circumferential hoop lying outside the open end of the shell; acounter-hoop lying over the head hoop, the counter-hoop having aplurality of circumferentially-spaced inwardly-facing cam followers; andmeans for rotating the counter-hoop about the drum axis with respect tothe drum shell; the drum also including a shell ring attached to andsurrounding the shell in the vicinity of the open end and a compressionring located between the counter-hoop and the head hoop; the shell ringhaving a plurality of circumferentially-spaced, outwardly facing cammembers which respectively engage the counter-hoop cam followers.

However, a simpler arrangement may be advantageous in certaincircumstances. It is therefore an object of the present invention toprovide a drum in which the drum skin can be tensioned and tuned in asingle operation and which is simpler in construction than existingdesigns.

SUMMARY OF THE INVENTION

According to the invention, there is provided a drum comprising: a drumshell, a drum head having a skin extending over an open end of the shelland a circumferential hoop lying outside the open end of the shell; acounter-hoop lying over the head hoop; and a shell ring fixed relativeto and surrounding the shell in the vicinity of the open end; thecounter-hoop and the shell hoop each having a radially outwardlyextending portion, the outwardly extending portions being such that thecounter-hoop portion is inclined downwards and/or the shell hoop portionis inclined upwards; the drum also including a clamp ring whichsurrounds the drum shell and engages the two outwardly extendingportions, the clamp ring being capable of radial expansion andcontraction.

Thus, as the clamp ring contracts, it exerts an inward compression forcewhich tends to draw the counter-hoop towards the shell hoop whichtensions the drum skin.

The counter-hoop bears directly on the head hoop. However, optionally, acompression ring may be located between the counter-hoop and the headhoop. The location of the shell ring can be achieved with considerableaccuracy, thus minimising the likelihood of uneven forces being appliedto the head hoop by the counter-hoop.

The outwardly extending portion of the counter-hoop is preferably acontinuous flange. The shell hoop may be discontinuous and may even beconstituted by circumferentially spaced blocks or bosses, however, theshell hoop is preferably a continuous ring and the outwardly extendingportion is preferably a continuous flange. The shell hoop may bescrewed, bolted or glued to the shell and/or is preferably let into achannel formed in the shell. When the shell hoop is let into a channel,it may have a breach so that it may be snapped into place. An outerclamp ring (such as a hose-clip) may be used additionally to hold theshell hoop in place.

Preferably, the counter-hoop is of stainless steel which is preferablypolished. The compression ring (if included) may be of any suitabledeformable material and is preferably also resilient; a convenientmaterial is NEOPRENE (T.M.).

The clamp ring is preferably made of a strong non-elastic but resilientmaterial such as steel. It preferably includes radially inwardlyextending rails which are inclined in a way which corresponds to anyinclination of the outwardly extending portions of the counter-hoop andshell hoop. Preferably, the inclinations are symmetrical.

The clamp ring may be radially contractable by reducing itscircumferential length. This may be achieved by the clamp ring being inthe form of a breached circular band; by moving the ends at the breachrelative to each other circumferentially, the effective circumference ofthe clamp ring can be varied. In order to control this adjustment, theclamp ring may have a screw thread arrangement spanning the breach.Preferably a first end of the clamp ring on one side of the breach hasan internally threaded member, while the second end of the clamp ring onthe other side of the breach has a bush. A bolt may then pass throughthe bush and into the threaded member, so that as the bolt is rotated,it is drawn through the threaded member and the bolt head will S bearagainst the bush. Continued rotation will move the bush towards thethreaded member and so tighten the clamp ring.

Alternatively, the clamp ring may be in the form of a circular band withoverlapping ends; by moving the end circumferentially the effectivecircumference of the clamp ring can be varied. The clamp ring may beprovided with a rack and pinion, or a worm gear in order to achieve thedesired adjustability.

In a further alternative, the clamp ring may comprise a series ofsegments with a cross-section as described above. The segments areattached to an outer ring or band. The attachment may be by means ofwelding, rivets, bolts etc. There may be four or more segments; six oreight might be typical though a greater number may be appropriate in thecase of larger drums. This arrangement may be particularly applicablefor drums such as tympanis when precise tuning is of great importance.

Preferably, the clamp ring is hinged in a position remote from thebreach, conveniently at a position opposite the breach. This arrangementwill allow the clamp ring to be fitted in position more readily.Preferably, the hinge connection is an adjustable, quick-releasemechanism. In this way, the clamp ring can not only be opened but canalso be released and removed very rapidly. If necessary, coarseadjustment of the clamp ring can be effected before the clamp ring isre-fitted.

The invention may be particularly applicable to tympanis. Thecounter-hoop could be reduced in height in order that it should notprotrude above the level of the drum skin. In order to tune theinstrument, a flexible drive may be provided, connected to a foot pedal.The drive would then also engage the bolt. As the foot pedal isoperated, the bolt is tightened or loosened and the pitch of the skin isadjusted. Alternatively, an electrical drive operated by the foot pedalcould be employed to rotate the bolt.

The invention can also be applied to toy drums, tambourines, bongo drumsand other drums played by the hands. Again, the counter-hoop would bereduced in height to avoid a rim protruding above the level of the skin.

Possibly, a series of buffers may be provided on the drum shell, inorder to protect the surface of the shell. The buffers are preferablyarranged circumferentially about the shell near the top and bottom. Theymay each comprise a resilient insert in a metal housing. The insert ispreferably of SANTOPRENE (T.M.) and the housing of polished stainlesssteel. The buffers are of particular benefit when different sized drumsare stored one inside the other, a realistic possibility in accordancewith the invention in view of the fact that the heads can be removedvery simply.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may be carried into practice in various ways and oneembodiment will now be described by way of example with reference to theaccompanying drawings, in which:

FIG. 1 is a partial vertical section through one wall of a drum inaccordance with the present invention;

FIG. 2 is a view similar to FIG. 1 showing the drum head tensioned;

FIG. 3 is a plan view of the clamp ring tensioning mechanism;

FIG. 4 is a side view of the clamp ring tensioning mechanism;

FIG. 5 is a plan view of the clamp ring hinge;

FIGS. 6 and 7 are views similar to FIGS. 1 and 2 showing a second, andpreferred, embodiment;

FIG. 8 is a plan view of a preferred quick-release mechanism; and

FIG. 9 is a partial vertical section through one wall of a drum inaccordance with another embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

As shown in FIGS. 1 and 2, the drum comprises a drum shell 11, a drumhead 12, a counter-hoop 13, and a shell hoop 15. The drum shell 11 is ofstandard laminated resin bonded hardwood construction. It is cylindricaland open ended. The shell hoop 15 is of polished stainless steel and isrigidly attached around the top of the shell 11. The shell hoop has arim 16 which extends upwardly and outwardly.

The head 12 comprises a skin 17 and a flesh hoop or bead 18 at itsperiphery. The bead 18 is located outside the drum shell 11 so that theskin 17 stretches over the open end. The counter-hoop 13 is of polishedstainless steel and has a downwardly and outwardly extending flange 19.The flange 19 of the counter-hoop 13 bears on the bead 18.

The counter-hoop 13 is held in position by a clamp ring 21. The clampring 21 is a steel band with a C-shaped cross-section comprising agenerally flat spine 22 with upper and lower skirts 23,24. The skirts23,24 extend inwardly and diverge with inclinations corresponding tothose of the rim 16 and flange 19. Thus, when in position, the upperskirt 23 fits over the flange 19 on the counter-hoop 13 and the lowerskirt 24 fits beneath the shell hoop rim 16.

As shown in FIGS. 3, 4 and 5, the clamp ring 21 has a breach 41 definingtwo ends 42,43 and, diametrically opposite, a hinge 44. A threaded nut45 is attached to one end 42 of the clamp ring 21 and a bush 46 isattached to the other end 43. A threaded bolt 47 with a head 48 passesthrough the bush 46 and engages the nut 45. The bolt head 48 has ahexagonal portion 49 and a through-hole 51 passing through the head atright angles to the bolt axis.

In use, when the components are assembled, the head 12 is placed overthe open end of the shell 11 and the counter-hoop 13 is located on thebead 18. The clamp ring 21 is then located outside the counter-hoop 13and shell ring 15. This is facilitated by the hinge 44, which allows theclamp ring 21 to open. The bolt 47 is then tightened (either by thehexagonal head 49 or by a metal rod or the like passing through thethrough-hole 51) and the clamp ring 21 is constricted. As the clamp ring21 constricts, the skirts 23,24 engage the flange 19 and rim 16, solocating the counter-hoop 13. As the clamp ring 21 is tightened further,the counter-hoop 13 is drawn down by the dual camming action of the twoskirts 23,24.

This in turn exerts a downward pressure on the bead 18 which stretchesthe skin 17 evenly over the rim of the shell 11. To remove the skin 12,it is simply necessary to reverse the operation, or to open the quickrelease mechanism.

It has been found in practice that with this arrangement it is possibleto achieve a downward movement of the counter-hoop 13 of up to 6 mm,from the point at which the counter-hoop 13 engages the bead 18. This ismore than sufficient to enable the drum skin 17 to be tuned.

The embodiment shown in FIGS. 6 and 7 is similar to the previousembodiment other than in the form and disposition of the shell hoop. Inthis embodiment, a channel 61 is formed around the periphery of the drumshell 11, near the top. A shell hoop 62 is located in this channel andmay be fixed in position by means of a suitable adhesive and/or bolts orthe like though this may not be necessary.

The shell hoop 62 comprises a vertical upwardly extending skirt 63 andan upwardly and outwardly inclined rim 64. The skirt 63 sits in thechannel 61. The inclined rim 64 is turned inwards at its outer peripheryand cooperates with the lower skirt 24 of the clamp ring 21.

The arrangement has the advantage that as the clamp ring 21 istightened, there is no tendency to pull the shell hoop 62 away from thedrum shell 11. On the contrary, the shell hoop 62 is forced into closercontact with the drum shell 11 as the clamp ring 21 is tightened.

A further advantage is that there is probably no real need for the shellhoop 62 to be positively attached to the drum shell 11. This in turnmeans that the drum shell does not need to be drilled to accept boltsand so the integrity of the drum shell 11 is maintained.

In a preferred embodiment as shown in FIG. 8 the hinge takes the form ofan adjustable, quick release mechanism 71. Effectively, therefore, theclamp ring 21 comprises two half-circles, joined at one breach 41 bymeans of the nut 45, the bush 46 and the bolt 47, and joined at theother breach 72 by means of the adjustable quick-release mechanism 71.

The quick release mechanism 71 comprises a pair of hook members 73 (oneof which is shown), a yoke 74, a lever 75 and a bolt 76 which carries athreaded, two-headed nut 77. The hook members 73 are fixed to the clampring 21 on one side of the breach 72 while the yoke 74 is fixed to theclamp ring 21 on the other side of the breach 72.

The bolt 76 is pivot ally attached to the lever 75 at a rear pivot point78 while the lever 75 is pivotally mounted on the yoke 74 at forwardpivot point 79. In the closed position, the two heads of the nut 77 arelocated behind the hook members 73.

Due to the relative locations of the pivot points 78,79, forwardmovement of the lever 75 moves the heads of the nut 77 out of engagementwith the hook members 73, thus releasing the mechanism. To re-lock themechanism, the heads of the nut 77 are located behind the hook memberswith the lever 75 in the forward position, and the lever 75 is thenmoved back to the position shown in FIG. 8. This draws back the bolt 76and locates the heads of the nut 77 behind the hook members 73.

It will be appreciated that by moving the nut 77 along the bolt 76, theeffective circumference of the clamp ring 21 can be adjusted, thusvarying the tension in the clamp ring 21.

In the embodiment shown in FIG. 9, the drum comprises a drum shell 111,a drum head 112, a counter-hoop 113, a compression ring 114 and a shellhoop 115. The compression ring 114 is located between the flange 119 ofthe counter-hoop 113 and the bead 118.

The counter-hoop 113 is held in position by a clamp ring 121. The clampring 121 is a steel band with overlapping ends, and a C-shapedcross-section comprising a generally flat spine 122 with upper and lowerskirts 123,124. The skirts 123,124 extend inwardly and diverge withinclinations corresponding to those of the rim 116 and flange 119. Thus,when in position, the upper skirt 123 fits over the flange 119 on thecounter-hoop 113 and the lower skirt 124 fits beneath the shell hoop rim116.

The clamp ring 121 also has a worm gear mechanism 125. The spine 122, inthe region of the overlapping ends of the band, is formed with teeth 126which mesh with corresponding teeth 127 on a worm drive 128. The wormdrive 128 is attached to the underlying section of the band (not shown).

Optionally, the drum may be provided with a series of buffers 131 whichare bolted to the shell 111. The buffers 131 each comprise a resilientinsert 132 located within a polished stainless steel cup 133 which isbolted through the shell 111.

In use, when the components are assembled, the head 112 is placed overthe open end of the shell 111, the compression ring 114 is located onthe bead 118 and the counter-hoop 113 is rested on the compression ring114. The clamp ring 121 is then located outside the counter-hoop 113 andshell ring 115 and is tightened using the worm gear 125. Any slightunevenness in the skin 117 is compensated for by the compression ring114.

What is claimed is:
 1. A drum comprising:a drum shell having an openend; a drum head having a skin extending over the open end of the shelland a circumferential head hoop lying outside the open end of the shell;a counter-hoop lying over the circumferential head hoop; a shell hoopfixed relative to and surrounding the shell in the vicinity of the openend; and a clamp ring surrounding the drum shell; and wherein thecounter-hoop and the shell hoop each have a radially outwardly extendingportion the respective outwardly extending portions being such that thecounter-hoop portion is inclined away from the open end of the shell andthe shell hoop portion is inclined towards the open end of the shell;the clamp ring being arranged to engage the two outwardly extendingportions and being capable of radial expansion and contraction; theclamp ring including radially inwardly extending rails which areinclined in a way which corresponds to any inclination of the respectiveoutwardly extending portion of the counter-hoop and shell hoop.
 2. Adrum as claimed in claim 1, wherein the outwardly extending portion ofthe counter-hoop is inclined downwards while the outwardly extendingportion of the shell hoop is conversely inclined upwards.
 3. A drum asclaimed in claim 1, wherein the outwardly extending portion of thecounter-hoop is a continuous flange.
 4. A drum as claimed in claim 1,wherein the shell hoop is a continuous ring including a breach, and theoutwardly extending portion is a flange which is continuous other thanin the position of the breach.
 5. A drum as claimed in claim 1, whereinthat the shell hoop is let into a channel formed in the shell.
 6. A drumas claimed in claim 1, wherein the counter-hoop is of stainless steel.7. A drum as claimed in claim 1, wherein the clamp ring is in the formof a circular band with a breach and two ends at the breach, the twoends being movable relative to each other in a circumferential sensewhereby the circumference of the clamp ring can be varied.
 8. A drum asclaimed in claim 7, wherein the clamp ring includes a screw threadarrangement spanning the breach.
 9. A drum as claimed in claim 8,wherein a first end of the clamp ring on one side of the breach has aninternally threaded member while the second end of the clamp ring on theother side of the breach has a bush, and a bolt passes through the bushand into the threaded member.
 10. A drum as claimed in claim 7, whereinthe clamp ring includes a hinge in a position remote from the breach.11. A drum as claimed in claim 10, wherein the hinge is an adjustablequick release mechanism.
 12. A drum as claimed in claim 2, wherein theoutwardly extending portion of the counter-hoop is a continuous flange.13. A drum as claimed in claim 2, wherein the shell hoop is a continuousring including a breach, and the outwardly extending portion is a flangewhich is continuous other than in the position of the breach.
 14. A drumas claimed in claim 13, wherein the shell hoop is let into a channelformed in the shell.
 15. A drum as claimed in claim 14, wherein theclamp ring is in the form of a circular band with a breach and two endsat the breach, the two ends being movable relative to each other in acircumferential sense whereby the circumference of the clamp ring can bevaried.
 16. A drum as claimed in claim 15, wherein the clamp ring ishinged in a position remote from the breach.
 17. A drum comprising:adrum shell having an open end; a drum head having a skin extending overthe open end of the shell and a circumferential head hoop lying outsidethe open end of the shell; a counter-hoop lying over the circumferentialhead hoop; a shell hoop fixed relative to and surrounding the shell inthe vicinity of the open end; and a clamp ring surrounding the drumshell; and wherein the counter-hoop and the shell hoop each have aradially outwardly extending portion the respective outwardly extendingportions being such that the counter-hoop portion is inclined away fromthe open end of the shell and the shell hoop portion is inclined towardsthe open end of the shell; the clamp ring being arranged to engage thetwo outwardly extending portions and being capable of radial expansionand contraction; the clamp ring being in the form of a circular bandwith a breach and two ends at the breach, the two ends being movablerelative to each other in a circumferential sense whereby thecircumference of the clamp ring can be varied.
 18. A drum as claimed inclaim 17, wherein the outwardly extending portion of the counter-hoop isinclined downwards while the outwardly extending portion of the shellhoop is conversely inclined upwards.
 19. A drum as claimed in claim 17,wherein the shell hoop is a continuous ring including a breach, and theoutwardly extending portion is a flange which is continuous other thanin the position of the breach.
 20. A drum as claimed in claim 19,wherein the clamp ring includes radially inwardly extending rails whichare inclined in a way which corresponds to any inclination of therespective outwardly extending portion of the counter-hoop and shellhoop.
 21. A drum comprising:a support having an end; a drum head havinga skin extending over the end of the support and a circumferential headhoop lying outside the end of the support; a counter-hoop lying over thecircumferential head hoop; a support hoop fixed relative to andsurrounding the support in the vicinity of the end; and a clamp ringsurrounding the support; and wherein the counter-hoop and the supporthoop each have a radially outwardly extending portion, the respectiveoutwardly extending portions being such that the counter-hoop portion isinclined away from the end of the support and the support hoop portionis inclined towards the end of the support; the clamp ring beingarranged to engage the two outwardly extending portions and beingcapable of radial expansion and contraction; the clamp ring includingradially inwardly extending rails which are inclined in a way whichcorresponds to any inclination of the respective outwardly extendingportion of the counter-hoop and support hoop.
 22. A drum as claimed inclaim 21, wherein the support comprises a drum shell.
 23. A drum asclaimed in claim 21, wherein the support has a cylindrical shape.
 24. Adrum as claimed in claim 21, wherein the support is of laminated resinbonded hardwood construction.
 25. A drum as claimed in claim 21, whereinthe support is in supporting contact with the skin.
 26. A drum asclaimed in claim 21, wherein the end is an open end of the support. 27.A drum as claimed in claim 21, wherein the clamp ring is in the form ofa circular band with a breach and two ends at the breach, the two endsbeing movable relative to each other in a circumferential sense wherebythe circumference of the clamp ring can be varied.